Copper-silver-phosphate nanoparticle manufacturing method

ABSTRACT

A method of making Cu—Ag3PO4 nanoparticles is provided. The method includes forming a mixture of at least one silver salt, at least one phosphate salt, and at least one copper (II) salt. The method further includes dissolving the mixture in water. The method further includes sonicating the mixture. The method further includes precipitating the Cu—Ag3PO4 nanoparticles or “nanoparticles”. The copper is present in the nanoparticles in an amount of 2 to 23 weight percent (wt.%) based on the total weight of the Cu—Ag3PO4. The nanoparticles of the present disclosure find application in treating cervical cancer, and colorectal cancer. The nanoparticles may also be used in photodegrading environmental pollutants.

BACKGROUND Technical Field

The present disclosure is directed to a method for preparing nanoparticles, nanoparticles obtained by the method, pharmaceutical compositions containing the nanoparticles, and particularly to a method of preparing Cu—Ag₃PO₄ nanoparticles for treating cervical and colorectal cancers.

Description of Related Art

The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present invention.

Treatments for cancers such as cervical cancer and colorectal cancer typically include surgery, radiation therapy, and/or chemotherapy. However, a continued high mortality of cancer patients reveals shortcomings of such treatments. Radiation therapy and chemotherapy have poor selectivity between cancerous and non-cancerous cells, thereby damaging healthy tissue. Many conventional anticancer pharmaceutical compositions for cancer treatments can suffer from the drawbacks of poor solubility, toxicity, and inefficacy. Therefore, treatments which can selectively target cancerous cells offer an advantage over the current technology.

Nanomaterials have the potential to selectively and directly target cancerous cells, leading to a decreased risk to healthy tissue in the patient and an overall increased chance of survival. Nanomaterials typically have unique properties over macromolecules, such as a high surface-to-volume ratio, enhanced electrical conductivity, superparamagnetic behavior, spectral shift of optical absorption, and unique fluorescence which allow them to be uniquely utilized in cancer treatment. Currently, nanomaterials are most commonly used in cancer treaments to enhance targeted drug delivery, and imaging.

Accordingly the present disclosure describes methods for making new nanomaterial compositions and the nanomaterial compositions obtained therefrom, where such nanomaterial compositions are easily synthesized, capable of selectively inducing toxicity to cancerous cells, and important to improving cancer treament.

SUMMARY

The present invention provides a method of making Cu—Ag₃PO₄ nanoparticles and treating cancer using said nanoparticles. In an exemplary embodiment, a method of making Cu—Ag₃PO₄ nanoparticles is described. The method includes forming a mixture of at least one silver salt, at least one phosphate salt, and at least one copper (II) salt. The method further includes dissolving the mixture in water. The method further includes sonicating the mixture and precipitating the sonicated mixture to obtain the Cu—Ag₃PO₄ nanoparticles. Copper is present in the nanoparticles in an amount of 2 to 23 weight percent (wt.%) based on the total weight of the Cu—Ag₃PO₄.

In some embodiments, the method of forming the mixture includes dissolving the copper (II) salt in water to form a dissolved copper (II) salt. Subsequently, the silver salt is mixed into the dissolved copper (II) salt to form a solution. Furthermore, the phosphate salt is dissolved in water and mixed dropwise into the solution. The solution including the mixture of the three salts is then sonicated for at least one hour.

In some embodiments, the method further includes centrifuging the mixture and removing excess liquid from precipitated Cu—Ag₃PO₄ nanoparticles. The precipitated Cu—Ag₃PO₄ nanoparticles may be further washed with ethanol and water, followed by drying the washed Cu—Ag₃PO₄ nanoparticles at a temperature less than 150° C. (°C).

In some embodiments, the silver salt is silver nitrate, the phosphate salt is disodium hydrogen phosphate, and the copper (II) salt is copper (II) oxide (CuO). In some embodiments, the method of making the CuO includes dissolving copper nitrate trihydrate in water in a polytetrafluoroethylene (PTFE) or Teflon® lined autoclave to form a dissolved copper nitrate trihydrate. The method further includes mixing trisodium citrate and ammonium fluoride into the dissolved copper nitrate trihydrate at a temperature less than 23° C. to form a solution. The method further includes heating the solution in the PTFE or Teflon® lined autoclave at a temperature over 120° C. for more than 10 hours, followed by centrifuging the heated solution and removing excess liquid from a precipitate. The method further includes washing the precipitate with ethanol and water, followed by drying the washed precipitate at a temperature less than 150° C., and calcining the dried precipitate at a temperature greater than 300° C. to form CuO.

In some embodiments, the Cu—Ag₃PO₄ nanoparticles include a copper content of 2-7 wt.%, a mean surface area of 2.5-3.5-meter square per gram (m²/g), a mean pore size of 20-30 nanometer (nm), and a mean pore volume of 100-200 centimeter cube per gram (cm³/g).

In some embodiments, the Cu—Ag₃PO₄ nanoparticles include a copper content of 8-13 wt.%, a mean surface area of 3.8-4.8 m²/g, a mean pore size of 25-35 nm, and a mean pore volume of 100-200 cm³/g.

In some embodiments, the Cu—Ag₃PO₄ nanoparticles include a copper content of 14-18 wt.%. The Cu—Ag₃PO₄ nanoparticles further include a mean surface area of 5.5-6.5 m²/g, a mean pore size of 15-25 nm, and a mean pore volume of 200-300 cm³/g.

In some embodiments, the Cu—Ag₃PO₄ nanoparticles include a copper content of 19-23 wt.%. The Cu—Ag₃PO₄ nanoparticles further include a mean surface area of 6.5-7.5 m²/g, a mean pore size of 20-30 nm, and a mean pore volume of 250-350 cm³/g.

In some embodiments, the Cu—Ag₃PO₄ nanoparticles are substantially spherical and the Cu—Ag₃PO₄ nanoparticles have a mean particle size of 100-1000 nm.

In some embodiments, a method of treating cervical cancer, colorectal cancer, or both in a subject includes administering to the subject an effective amount of the Cu—Ag₃PO₄ nanoparticles prepared by the method of the present disclosure to decrease the average cancer cell viability by more than 10%.

In some embodiments, a cervical cancer treating composition includes 2-7 wt.% copper Cu—Ag₃PO₄ nanoparticles prepared by the method of the present disclosure. The composition has a half-maximal inhibitory concentration (IC₅₀) of 69-73 microgram per milliliter (µg/mL) for HeLa cells.

In some embodiments, a cervical cancer treating composition includes 8-13 wt.% copper Cu—Ag₃PO₄ nanoparticles prepared by the method of the present disclosure. The composition has a IC₅₀ of 95-105 µg/mL for HeLa cells.

In some embodiments, a cervical cancer treating composition includes 14-18 wt.% copper Cu—Ag₃PO₄ nanoparticles prepared by the method of the present disclosure. The composition has a IC₅₀ of 54-63 µg/mL for HeLa cells.

In some embodiments, a cervical cancer treating composition includes 19-23 wt.% copper Cu—Ag₃PO₄ nanoparticles prepared by the method of the present disclosure. The composition has a IC₅₀ of 45-55 µg/mL for HeLa cells.

In some embodiments, a colorectal cancer treating composition includes 2-7 wt.% copper Cu—Ag₃PO₄ nanoparticles prepared by the method of making Cu—Ag₃PO₄ nanoparticles. The composition has a IC₅₀ of 66-68 µg/mL for HCT-116 cells.

In some embodiments, a colorectal cancer treating composition includes 8-13 wt.% copper Cu—Ag₃PO₄ nanoparticles prepared by the method of the present disclosure. The composition has a IC₅₀ of 35-45 µg/mL for HCT-116 cells.

In some embodiments, a colorectal cancer treating composition includes 14-18 wt.% copper Cu—Ag₃PO₄ nanoparticles prepared by the method of the present disclosure. The composition has a IC₅₀ of 35-45 µg/mL for HCT-116 cells.

In some embodiments, a colorectal cancer treating composition includes 19-23 wt.% copper Cu—Ag₃PO₄ nanoparticles prepared by the method of the present disclosure. The composition has a IC₅₀ of 45-55 µg/mL for HCT-116 cells.

In another exemplary embodiment, a method of photodegrading environmental pollutants is described. The method of photodegrading environmental pollutants includes contacting the Cu—Ag₃PO₄ nanoparticles prepared by the method of the present disclosure and the environmental pollutant. The method of photodegrading environmental pollutants further includes exposing the solution to light and oxygen.

The foregoing general description of the illustrative present disclosure and the following detailed description thereof are merely exemplary aspects of the teachings of this disclosure and are not restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of this disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

FIG. 1 is a schematic flow diagram of a method of making Cu—Ag₃PO₄ nanoparticles, according to certain embodiments.

FIG. 2 is a schematic flow diagram of a method of making copper oxide (CuO), according to certain embodiments.

FIG. 3 is a combined X-Ray Diffraction (XRD) image of the Cu—Ag₃PO₄ nanoparticles with varying weight percentages, 5% Cu—Ag₃PO₄ (3A), 10% Cu—Ag₃PO₄ (3B), 15% Cu—Ag₃PO₄ (3C) 20% Cu—Ag₃PO₄ nanoparticles (3D), according to certain embodiments.

FIGS. 4A-4D are Scanning Electron Microscope (SEM) images of the Cu—Ag₃PO₄ nanoparticles with varying weight percentages, 5% Cu—Ag₃PO₄ (4A), 10% Cu—Ag₃PO₄ (4B), 15% Cu—Ag₃PO₄ (4C), 20% Cu—Ag₃PO₄ nanoparticles (4D), according to certain embodiments.

FIGS. 5A-5D are Energy Dispersive X-Ray Analysis (EDX) spectra and elemental mapping of the Cu—Ag₃PO₄ nanoparticles with varying weight percentages, 5% Cu—Ag₃PO₄ (5A), 10% Cu—Ag₃PO₄ (5B), 15% Cu—Ag₃PO₄ (5C), 20% Cu—Ag₃PO₄ nanoparticles (5D), according to certain embodiments.

FIG. 6 is a graphical representation of N₂ adsorption-desorption isotherms for the Cu—Ag₃PO₄ nanoparticles with varying weight percentages, according to certain embodiments.

FIG. 7 is a combined Fourier Transform Infrared Spectrum (FTIS) of Cu—Ag₃PO₄ nanoparticles with varying weight percentages, according to certain embodiments.

FIG. 8 is a combined Ultraviolet-visible (UV-Vis) spectrum of the Cu—Ag₃PO₄ nanoparticles with varying weight percentages, according to certain embodiments.

FIG. 9 is a statistical representation of the cell viability assay of control cells and after treatment of HCT-116, HeLa, and HEK-293 cells with Cu—Ag₃PO₄ nanoparticles, according to certain embodiments.

FIGS. 10A-10E are morphological images of colorectal cancer cells (HCT-116) stained with 4′,6-diamidino-2-phenylindole (DAPI), 48 hours after treatment with 25 µg/mL of Cu—Ag₃PO₄ nanoparticles, Control (10A), 5% Cu—Ag₃PO₄ (10B), 10% Cu—Ag₃PO₄ (10C), 15% Cu—Ag₃PO₄ (10D), 20% Cu—Ag₃PO₄ nanoparticles (10E), according to certain embodiments. Arrows show the nuclear condensation, fragmentation, and cell membrane disruption.

DETAILED DESCRIPTION

In the drawings, like reference numerals designate identical or corresponding parts throughout the several views. Further, as used herein, the words “a,” “an” and the like generally carry a meaning of “one or more,” unless stated otherwise.

Furthermore, the terms “approximately,” “approximate,” “about,” and similar terms generally refer to ranges that include the identified value within a margin of 20%, 10%, or preferably 5%, and any values there between.

Embodiments of the present disclosure are directed to a method for making Cu—Ag₃PO₄ nanoparticles or “nanoparticles”. The method is based on ultrasonic assisted synthesis of Cu—Ag₃PO₄ nanoparticle-containing compositions of varying copper concentrations, particularly, 5% Cu—Ag₃PO₄, 10% Cu—Ag₃PO₄, 15% Cu—Ag₃PO₄, and 20% Cu—Ag₃PO₄, respectively. The prepared nanoparticles were characterized by various analytical techniques, and their impact on cancer cells was studied. Although the description herein refers to the use of the nanoparticles for treatment of cervical and colon cancers, it may be understood by a person skilled in the art, that aspects of the present disclosure may be directed towards treatment of other cancers such as, cancer of thyroid, endocrine system, brain, breast, cervix, ovary, sarcoma, stomach, uterus medulloblastoma, colon, head and neck, liver, kidney, lung, non-small cell lung, melanoma, mesothelioma, or pancreatic cancer, as well. Cell viability studies with the nanoparticles of the present disclosure demonstrated that a significant decrease in cell viability was observed on both colon cancer (HCT-116) and cervical cancer (HeLa) cells, after the cells were treated with the nanoparticles prepared by the process of the present disclosure. The nanoparticles prepared by the process of the present disclosure are effective on both colon cancer, and cervical cancer cells at low concentrations (µg/mL), thereby circumventing the drawbacks such as drug induced toxicity, of the prior art.

Referring to FIG. 1 , a schematic flow diagram of a method 100 of making Cu—Ag₃PO₄ nanoparticles is illustrated. The method 100 is described with reference to formation of CuO illustrated in FIG. 2 . The order in which the method 100 is described is not intended to be construed as a limitation, and any number of the described method steps can be combined in any order to implement the method 100. Additionally, individual steps may be removed or skipped from the method 100 without departing from the spirit and scope of the present disclosure.

At step 102, the method 100 includes forming a mixture of at least one silver salt, at least one phosphate salt, and at least one copper (II) salt. The silver salt can be silver halide, silver sulfate, silver phosphate, silver carbonate, silver acetate, or a silver nitrate, and hydrates thereof. In an embodiment, the silver salt is silver nitrate. The phosphate salt can be alkali metals or alkaline earth metals, with monophosphates, diphosphates, or polyphosphates, and hydrates thereof. In an embodiment, the phosphate salt is disodium hydrogen phosphate. The copper (II) salt can be oxides, hydroxides, carbonates, sulfates, halides, or nitrates of copper, and hydrates thereof. In an embodiment, the copper salt is copper (II) oxide (CuO).

At step 104, the method 100 includes dissolving the mixture in water. In an embodiment, each of the salts, namely, the copper salt, phosphate salt, and the silver salt, may be dissolved in water individually or in combination. In an embodiment, the copper (II) salt is dissolved in water to form a dissolved copper (II) salt. To the dissolved copper (II) salt, was added the silver salt to form a solution. In an embodiment the solution was then exposed to ultraviolet radiation, 200-400 nm at 36 W for 5 minutes. The phosphate salt, dissolved in water, was added to the solution in a dropwise manner.

At step 106, the method 100 includes sonicating the mixture. The solution containing the mixture of the three salts, namely, the copper salt, phosphate salt, and the silver salt, is sonicated for at least one hour. Sonication can take place at a frequency greater than 20 kilohertz (kHz), preferably 20-60 kHz, and a power of 90-250 watts (W). In an embodiment, the solution is sonicated for 1 hour at a frequency of 20 kHz, and a power of 125 W. Advantageous combinations of pore size and pore volume are obtained under particular sonication conditions including the amount of copper. Sonication in combination with exposure to ultraviolet light having a wavelength of in the range of 200-400 nm, desirably forms nanoparticles having a combination of large pore size and small pore volume. Sonication and UV light exposure may occur concurrently. UV light exposure is preferably carried out for a fraction of sonication time. For example, sonication of a mixture of metal salts for one hour preferably includes no more than 10% of total sonication time during which exposure to UV light occurs. Preferably, UV light exposure is conducted for a period of time that is 5-10% of the total time of sonication.

At step 108, the method 100 includes precipitating the Cu—Ag₃PO₄ nanoparticles. The nanoparticles were precipitated by addition of a non-solvent. The non-solvent can be a non-polar solvent such as but not limited to, alkanes such as pentane, hexane, and heptane, benzene, toluene, xylene, chloroform, diethyl ether, ethyl acetate, dichloromethane, and combinations thereof. The method 100 includes centrifuging the mixture at room temperature. The excess liquid was removed to obtain a precipitate of the Cu—Ag₃PO₄ nanoparticles. The precipitated nanoparticles may be further washed with a solvent. In an embodiment, the solvent is an alcohol or water or a combination of both. The alcohol can be ethanol, isopropyl alcohol, or any lower alcohol. In an embodiment, the solvent is ethanol and water. The washed nanoparticles may be further dried at a temperature less than 150° C. In an embodiment, the Cu—Ag₃PO₄ nanoparticles include a copper content of 2-7 wt.%. In an alternate embodiment, the Cu—Ag₃PO₄ nanoparticles include a copper content of 8-13 wt.%. In some embodiments, the Cu—Ag₃PO₄ nanoparticles include a copper content of 14-18 wt.%. In some embodiments, the Cu—Ag₃PO₄ nanoparticles include a copper content of 19-23 wt.%.

Referring to FIG. 2 , a schematic flow diagram of a method 200 of making copper oxide (CuO) is illustrated. The order in which the method 200 is described is not intended to be construed as a limitation, and any number of the described method steps can be combined in any order to implement the method 200. Additionally, individual steps may be removed or skipped from the method 200 without departing from the spirit and scope of the present disclosure.

At step 202, method 200 includes dissolving copper nitrate trihydrate in water in an autoclave to form a dissolved copper nitrate trihydrate. In an embodiment, the autoclave is lined with polytetrafluoroethylene (PTFE) or Teflon®. In an embodiment, the dissolved copper nitrate trihydrate is obtained by heating copper nitrate trihydrate solution in the PTFE or Teflon® autoclave.

At step 204, method 200 includes mixing trisodium citrate and ammonium fluoride into the dissolved copper nitrate trihydrate at a temperature less than 23° C. to form a solution.

At step 206, method 200 includes heating the solution in the PTFE or Teflon® autoclave at a temperature over 120° C. for more than 10 hours.

At step 208, method 200 includes centrifuging the heated solution and removing excess liquid from precipitate.

At step 210, method 200 includes washing the precipitate with ethanol and water.

At step 212, method 200 includes drying the washed precipitate at a temperature less than 150° C.

At step 214, method 200 includes calcining the dried precipitate at a temperature greater than 300° C. to form CuO.

In some embodiments, the Cu—Ag₃PO₄ nanoparticles prepared by the method 100 have a mean surface area of 2.5-7.5 m²/g, preferably 3.0-6.0 m²/g, 3.5-5.5 m²/g or 4.0-5.0 m²/g. In some embodiments the nanoparticles have a mean pore size of 15-35 nm, preferably 17-27 nm, or 20-25 nm. In some embodiments the nanoparticles have a mean pore volume of 100-350 cm³/g, preferably 150-300 cm³/g, or 200-250 cm³/g. In some embodiments, the Cu—Ag₃PO₄ nanoparticles are substantially spherical. In some embodiments, the Cu—Ag₃PO₄ nanoparticles have a mean particle size of 100-1000 nm, preferably 200-900 nm, 300-800 nm, 400-700 nm, or 500-600 nm. In one embodiment the nanoparticles have large pore size and small pore volume, for example, the pore size may range from 25-30 nm, preferably 26-29 nm or about 29.5 nm. Relatively large pore size contrasts with a pore volume that is relatively small, for example less than 0.015 cm³/g, preferably from 0.01 to 0.15 cm³/g. Relatively large pore size and small pore volume is indicative of a pore morphology that is wide and shallow. In this state the pore morphology may help docking with pharmaceutical materials and/or aid in approach to and ionic interaction/bonding with a cell or liposomal surface. This docking and/or bonding performance is especially noteworthy for HCT-116 cells.

In an aspect, the present disclosure provides a method of treating cervical cancer, colorectal cancer, or both in a subject by administering to the subject an effective amount of the Cu—Ag₃PO₄ nanoparticles prepared by the method 100. In the present embodiment, the subject is a human. In some embodiments, the subject may be an animal. Effective amount refers to a dose or concentration of a drug that produces a biological response. Herein the biological response refers to a decrease in cell viability following treatment with Cu—Ag₃PO₄ nanoparticles. The cell viability is the percentage of cells that survive following exposure to the nanoparticles. See Nawaz, et.al. Preparation of indium-cadmium sulfide nanoparticles with diverse morphologies: Photocatalytic and cytotoxicity study. Journal of Molecular Structure, 1253, (2022), 132288, incorporated herein by reference in its entirety. In an embodiment, the Cu—Ag₃PO₄ nanoparticles, prepared by the method 100, when administered to the subject decreases the average cancer cell viability by more than 10%, preferably 20% or more, 30% or more, 40% or more, 50% or more and most preferably leads to complete cell mortality.

The half-maximal inhibitory concentration (IC₅₀) was measured for the Cu—Ag₃PO₄ nanoparticles with HeLa cells, HCT-116 cells, HEK-293 cells. IC₅₀is defined as the concentration of the Cu—Ag₃PO₄ nanoparticles administered to cells that will inhibit their growth by 50%. In some embodiments, the Cu—Ag₃PO₄ nanoparticles, prepared by the method 100, have an IC₅₀ of 30-110 pg/mL, preferably 40-100 µg/mL, 50-90 pg/mL, or 60-80 µg/mL. Lower IC₅₀ values indicate an affinity of the Cu—Ag₃PO₄ nanoparticles for the cells as a lower concentration is needed to decrease cell viability.

Further, the present disclosure provides a method of photodegrading environmental pollutants. The method includes contacting the Cu—Ag₃PO₄ nanoparticles prepared by the method 100 and the environmental pollutant in a solution. The method further includes exposing the solution to light and oxygen. In some embodiments, the environmental pollutant is in an aqueous solution. In some embodiments the Cu—Ag₃PO₄ nanoparticles are dispersed in water before contacting with the solution. In some embodiments the Cu—Ag₃PO₄ nanoparticles are stirred into the solution to increase contact probability with the environmental pollutant. In some embodiments the environmental pollutant is present in the solution at 400 ppm or more. In some embodiments 1-500 mg/L, preferably 100-400 mg/L, or 200-300 mg/L of Cu—Ag₃PO₄ nanoparticles are contacted with the solution. The environmental pollutant can be aldehydes such as acetaldehyde and formaldehyde, carboxylic acids such as acetic acid and formic acid, aromatic compounds such as benzene, toluene, xylene, and halogenated benzene, alkyl halides, alcohols, ketones, esters, and hydrocarbons. The light can be a wavelength between 200-800 nm, preferably 200-450 nm, more preferably 200-300 nm, based on the absorbance of the Cu—Ag₃PO₄ nanoparticles in FIG. 8 .

EXAMPLES

The following examples describe and demonstrate exemplary embodiments of the Cu—Ag₃PO₄ nanoparticles described herein. The examples are provided solely for the purpose of illustration and are not to be construed as limitations of the present disclosure, as many variations thereof are possible without departing from the spirit and scope of the present disclosure.

Example 1: Materials Required

Precursor chemical salts such as copper nitrate trihydrate (CuH₆N₂O₉), trisodium citrate (Na₃C₆H₅O₇), ammonium fluoride (NH₄F), silver nitrate (AgNO₃) and disodium hydrogen phosphate (Na₂HPO₄) were used for Cu—Ag₃PO₄ nanoparticles synthesis. Further, water (H₂O) was also used.

Example 2: Method of Preparation of CuO

1 g copper nitrate trihydrate was dissolved in 30 mL of water in an autoclave lined with polytetrafluoroethylene (PTFE) or Teflon®, followed by addition of 0.3 g trisodium citrate and 0.3 g ammonium fluoride. The mixture was stirred at room temperature. Further, the autoclave was kept in an oven and heated at 150° C. for 15 hours. The autoclave was cooled at room temperature and precipitate was centrifuged, washed, dried, and calcined at 400° C. to give CuO (copper (II) oxide).

Example 3: Method of Preparation of Cu-Ag₃PO₄ Nanoparticles

To prepare Cu—Ag₃PO₄ nanoparticles, calculated amount of CuO (for 5, 10, 15 and 20 %) based on the weight of Cu—Ag₃PO₄, was dissolved in 30 mL of water, to which was added 0.5 g silver nitrate, to form a solution. After stirring the solution to allow for complete dissolution, 0.3 g disodium hydrogen phosphate (Na₂HPO₄) dissolved in 10 mL of water was added in a dropwise manner to the solution. The solution was further stirred for further 5 minutes to obtain a mixture. The mixture was sonicated for 1 hour and centrifuged to separate the supernatant and the precipitate. The precipitate was washed and dried to obtain the nanoparticles. Hence, products obtained were named as 5% Cu—Ag₃PO₄, 10% Cu—Ag₃PO₄, 15% Cu—Ag₃PO₄, and 20% Cu—Ag₃PO₄.

Experimental Experiment 1: In Vitro Cell Culture and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) Assay

Samples were treated with cancer cell lines such as human colorectal cancer cells (HCT-116) and human cervical cancer cells (HeLa) to study viability and proliferation of such cells. 5% Cu—Ag₃PO₄, 10% Cu—Ag₃PO₄, 15% Cu—Ag₃PO₄, and 20% Cu—Ag₃PO₄, as obtained in Example 2, are collectively referred to as ‘samples’ and individually referred to as ‘sample’ unless otherwise specified. Non-cancer cell line such as embryonic kidney cells (HEK-293) was considered as a control cell line. The cells were cultured and maintained in Dulbecco’s Modified Eagle Media (DMEM), L-glutamine (5%), penicillin (1%), streptomycin (1%), Fetal bovine serum (FBS) (10%), and selenium chloride (1%). The cells were grown in 96 well plates in a 5% CO₂ incubator (Thermo Fisher Scientific, Inc., Waltham, MA, USA) at 37° C., and 75-80% confluence cells and cell were processed for the MTT assay. The MTT assay is a colorimetric assay for measuring cell metabolic activity. The MTT assay is based on the ability of nicotinamide adenine dinucleotide phosphate (NADPH)-dependent cellular oxidoreductase enzymes to reduce the tetrazolium dye MTT to insoluble formazan, which has a purple colour.

The cells were treated with 5% Cu—Ag₃PO₄, 10% Cu—Ag₃PO₄, 15% Cu—Ag₃PO₄, and 20% Cu—Ag₃PO₄ with dosages ranging from 5.0 µg to 95 µg/mL for 48 hours. The treated cells were further processed to examine the cell viability using the MTT assay. The nanoparticles were not added to the control cell line. The embryonic kidney cells (HEK-293) were also treated with 5% Cu—Ag₃PO₄, 10% Cu—Ag₃PO₄, 15% Cu—Ag₃PO₄, and 20% Cu—Ag₃PO₄ with dosages ranging from 5.0 µg to 95 µg/mL. Both the control and treated groups (5% Cu—Ag₃PO₄, 10% Cu—Ag₃PO₄, 15% Cu—Ag₃PO₄, and 20% Cu—Ag₃PO₄) were treated with 10 µl of MTT (5 mg/mL), and cells were incubated in a CO₂ incubator for 4 hours. Further, cell culture media was replaced with DMSO (1%), and the 96-well plate was examined under an enzyme-linked immunoassay (ELISA) plate reader (Bio-tek Instruments, USA) at a wavelength of 570 nm. The percentage of cell viability was calculated for statistical analysis.

Experiment 2: Apoptotic DAPI (4′,6-diamidino-2-phenylindole) Staining

Morphology of cancer nuclear structure changes due to treatments with 5% Cu—Ag₃PO₄, 10% Cu—Ag₃PO₄, 15% Cu—Ag₃PO₄, and 20% Cu—Ag₃PO₄. The morphology changes were examined by DAPI staining assay. HCT-116 cells were divided into two groups such as a control group and an experimental group. No nanoparticles were added to the control group. However, 5% Cu—Ag₃PO4, 10% Cu—Ag₃PO₄, 15% Cu—Ag₃PO₄, and 20% Cu—Ag₃PO₄ (25 µg/mL) were added to the experimental group. Post 48 hours treatment, the control group and the experimental group were exposed to ice-cold (4%) paraformaldehyde and further with Triton X-100 in phosphate-buffered saline (PBS).

Further, the HCT-116 cells were stained with DAPI (1.0 µg/mL) for 5 minutes under a dark environment, and finally washed with PBS and cover-slipped. The deoxyribonucleic acid (DNA) staining was examined by using confocal scanning microscope (Zeiss, Germany). The data presented as mean (±) standard deviation (SD) obtained from triplicates and one-way analysis of variance (ANOVA) followed by Dennett’s post hoc test with GraphPad Prism Software (GraphPad Software, USA) for final statistical analysis.

Referring to FIG. 3 , an X-Ray Diffraction (XRD) image of 5% Cu—Ag₃PO₄, 10% Cu—Ag₃PO₄, 15% Cu—Ag₃PO₄, and 20% Cu—Ag₃PO₄ nanoparticles, is illustrated. The XRD is a technique employed to determine the underlying crystal structure of a material and enables verification of the crystallinity and structure of a sample. X-ray diffractometer (XRD, Rigaku, Japan) is used to study phases of Cu—Ag₃PO₄ nanoparticles in the range of 10-80° with 0.9°/ minute scanning speed. From the FIG. 3 , it can be observed that the material includes CuO, and Ag₃PO₄ particles which constitute to form Cu—Ag₃PO₄ nanoparticles.

Surface morphology and structure of the as-synthesized Cu—Ag₃PO₄ nanoparticles were evaluated by scanning electron microscopy (SEM) (Tscan); the images of which (5% Cu—Ag₃PO₄, 10% Cu—Ag₃PO₄, 15% Cu—Ag₃PO₄, and 20% Cu—Ag₃PO₄ nanoparticles) are presented in FIGS. 4A-4D, respectively. The nanoparticles are substantially spherical, however as the copper content increases the nanoparticles tend to aggregate to form clusters of particles. The average size of the nanoparticles is 400 nm, however there is a wide dispersion of sizes for the different copper contents.

Further, the elemental mapping of 5% Cu—Ag₃PO₄, 10% Cu—Ag₃PO₄, 15% Cu—Ag₃PO₄, and 20% Cu—Ag₃PO₄ nanoparticles was performed by Energy Dispersive X-ray spectroscopy (EDS) is to identify and quantify elemental compositions in the nanoparticles; the results of the present study are presented in FIGS. 5A to 5D. The presence of 4 peaks between 0.5 KeV and 4 KeV can be attributed to copper, silver, phosphorous and oxygen, confirming the formation of the nanoparticles. Quantitative analysis of the EDS spectra proved a high presence silver, and other elements being copper, phosphorous and oxygen, confirming the formation Cu-Ag₃PO₄ nanoparticles.

Referring to FIG. 6 , a graphical representation of N₂ adsorption-desorption isotherms for 5% Cu—Ag₃PO₄, 10% Cu—Ag₃PO₄, 15% Cu—Ag₃PO₄, and 20% Cu—Ag₃PO₄ (samples) nanoparticles is illustrated. A N₂ adsorption-desorption isotherm is a plot of relative pressure vs. volume adsorbed obtained by measuring the amount of N₂ gas that adsorbs onto the surface of a sorbate such as 5% Cu—Ag₃PO₄, 10% Cu—Ag₃PO₄, 15% Cu—Ag₃PO₄, and 20% Cu—Ag₃PO₄ nanoparticles, and the subsequent amount that desorbs at a constant temperature. The graphs confirm the existence of the mesoporous nanoparticles. The surface area of Cu—Ag₃PO₄ nanoparticles was studied by Brunauer-Emmett-Teller (BET) analyzer. The results of the present study are presented in Table 1. From the results as presented in Table 1, it can be observed that the pore volume and surface area of the Cu—Ag₃PO₄ nanoparticles increases as the percentage of copper in the nanoparticles increases. Whereas the pore size has an inversely proportional relationship to the percentage of copper in the nanoparticles. The 10% Cu—Ag₃PO₄ nanoparticles deviate from this trend by having the largest pore size and smallest pore volume, thereby wide and shallow pores.

TABLE 1 shows surface area, pore size and pore volume for the nanoparticles. Samples Surface area (m²/g) Pore size (nm) Pore volume (cm³/g) 5% Cu—Ag₃PO₄ 2.959 24.42 0.016 10% Cu—Ag₃PO₄ 4.282 29.635 0.014 15% Cu—Ag₃PO₄ 6.11 19.554 0.024 20% Cu—Ag₃PO₄ 7.0767 17.992 0.028

Referring to FIG. 7 , a combined Fourier Transform Infrared (FT-IR) spectrum of 5% Cu—Ag₃PO₄, 10% Cu—Ag₃PO₄, 15% Cu—Ag₃PO₄, and 20% Cu—Ag₃PO₄ nanoparticles is illustrated. FT-IR spectra are recorded on a Perkin Elmer spectrometer. FT-IR identifies chemical bonds in a molecule by producing an infrared absorption spectrum. The peaks at approximately 900 cm⁻¹ and 600 cm⁻¹ correspond to P—O bonds in the phosphate groups.

Referring to FIG. 8 , a combined Ultraviolet-visible (UV-vis) spectrum of 5% Cu—Ag₃PO₄, 10% Cu—Ag₃PO₄, 15% Cu—Ag₃PO₄, and 20% Cu—Ag₃PO₄ nanoparticles is illustrated. UV-visible spectrophotometer (JASCO V-750) is used to measure diffuse reflectance of Cu-Ag₃PO₄ nanoparticles. The spectra show a broad absorption of visible light by the nanoparticles.

The impact of 5% Cu—Ag₃PO₄, 10% Cu—Ag₃PO₄, 15% Cu—Ag₃PO₄, and 20% Cu-Ag₃PO₄ on both colon cancer (HCT-116) and cervical cancer (HeLa) cells was examined by performing cell viability assay and half-maximal inhibitory concentration (IC₅₀) studies. A statistical representation of the cell viability assay of control cells and after treatment of HCT-116, HeLa, and HEK-293 cells with Cu—Ag₃PO₄ nanoparticles is illustrated in FIG. 9 . Cell viability is a measure of the proportion of live, healthy cells within a population. Cell viability assays are used to determine the overall health of cells, establish culture or experimental conditions, and to measure cell survival following treatment with the nanoparticles. For the present purpose, HeLa, HCT-116 and HEK-293 cells (normal cells) stained with DAPI were treated with 5% Cu—Ag₃PO₄, 10% Cu—Ag₃PO₄, 15% Cu—Ag₃PO₄, and 20% Cu—Ag₃PO₄ nanoparticles followed by 48-hour treatment. The control cells were not treated with the nanoparticles. As can be observed from the FIG. 9 a significant decrease in colorectal cancer cells viability after treatment with 5% Cu—Ag₃PO₄, 10% Cu—Ag₃PO₄, 15% Cu—Ag₃PO₄, and 20% Cu—Ag₃PO₄. The presence of the nanoparticles leads to a decrease of cell viability when compared to a control deprived of any nanoparticles.

The IC₅₀ values with 5% Cu—Ag₃PO₄, 10% Cu—Ag₃PO₄, 15% Cu—Ag₃PO₄, and 20% Cu—Ag₃PO₄ on HCT-116, HeLa cells and HEK-293, were studied and the results of the present study are presented in Table 2. IC₅₀ is a quantitative measure that indicates how much of a particular inhibitory substance, in this study Cu—Ag₃PO₄ nanoparticles, is needed to inhibit cell viability by 50%.

TABLE 2 IC₅₀ value for Cu—Ag₃PO₄ nanoparticles (5, 10, 15 and 20 %) on HCT-116, HeLa cells and HEK-293 Samples HCT-116 (IC₅₀ (µg/mL)) HeLa (IC₅₀ (µg/mL)) HEK-293 (IC₅₀ (µg/mL)) 5% Cu—Ag₃PO₄ 67.00 ±1.0 µg/mL 70.83 ± 2.2 µg/mL 79.51 ±8.2 µg/mL 10% Cu—Ag₃PO₄ 40.00 ±4.2 µg/mL 100.00 ±4.2 µg/mL 50.00 ±4.2 µg/mL 15% Cu—Ag₃PO₄ 41.00 ±5.2 µg/mL 58.87 ±4.2 µg/mL 68.30 ±4.2 µg/mL 20% Cu—Ag₃PO₄ 50.00 ±4.2 µg/mL 50.00 ±4.2 µg/mL 100.00 ±4.2 µg/mL

The IC₅₀ value for 5% Cu—Ag₃PO₄, 10% Cu—Ag₃PO₄, 15% Cu—Ag₃PO₄, and 20% Cu—Ag₃PO₄ on HCT-116, HeLa cells and HEK-293 IC₅₀ was calculated, and it was observed to be in the range 40-100 µg/mL. From Table 2, it can be observed that in most cases, a lower concentration of Cu—Ag₃PO₄ nanoparticles is required to inhibit cancer cell viability as the amount of copper in the nanoparticle increases. Also, overall the IC₅₀ values are higher for normal HEK-293 than the cancer cells, therefore the nanoparticles have a higher affinity for cancer cells, especially the 20% Cu—Ag₃PO₄ which caused damage to the normal cells at a high concentration. The 10% Cu—Ag₃PO₄ nanoparticles have the lowest IC₅₀ value for the HCT-116 cells, indicating that their wide and shallow pores may have a stronger interaction with the HCT-116 cells.

FIGS. 10A-10E refer to morphological images of HCT-116 cells stained with DAPI post 48-hour treatment. FIGS. 10A-10E depict control cells; HCT-116 cells treated with 5% Cu—Ag₃PO₄; HCT-116 cells treated with 10% Cu—Ag₃PO₄; HCT-116 cells treated with 15% Cu—Ag₃PO₄; and HCT-116 cells treated with 20% Cu—Ag₃PO₄, respectively, with a dose of 25 µg/mL. The images show a decrease in the number of cells, nuclear condensation, fragmentation, and cell membrane disruption after exposure to Cu—Ag₃PO₄ nanoparticles. This clearly demonstrates that the Cu—Ag₃PO₄ nanoparticles are effective in decreasing cell viability even at µg/mL dosages.

Obviously, numerous modifications and variations of the present disclosure are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein. 

1. A method of making Cu—Ag₃PO₄ nanoparticles, comprising: forming a mixture of at least one silver salt, at least one phosphate salt, and at least one copper (II) salt; dissolving the mixture in water; sonicating the mixture; and precipitating the Cu—Ag₃PO₄ nanoparticles; wherein copper is present in the Cu—Ag₃PO₄ nanoparticles in an amount of 2 to 23 weight percent (wt.%) based on the total weight of the Cu—Ag₃PO₄ nanoparticles.
 2. The method of claim 1, further comprising: dissolving the copper (11) salt in water to form a dissolved copper (11) salt; mixing the silver salt into the dissolved copper (II) salt to form a solution; dissolving the phosphate salt in water to form a phosphate mixture and dropwise mixing the phosphate mixture into the solution; and sonicating the mixture for at least one hour.
 3. The method of claim 1, further comprising: centrifuging the mixture after the precipitating and separating precipitated Cu-Ag₃PO₄ nanoparticles; washing the precipitated Cu—Ag₃PO₄ nanoparticles with ethanol and water; and drying the washed Cu—Ag₃PO₄ nanoparticles at a temperature less than 150° C.
 4. The method of claim 1, wherein: the silver salt is silver nitrate; the phosphate salt is disodium hydrogen phosphate; and the copper (II) salt is copper (II) oxide (CuO).
 5. The method of claim 1, wherein: the copper (II) salt is CuO, and the CuO is made by a method comprising: dissolving copper nitrate trihydrate in water in a polytetrafluoroethylene (PTFE) lined autoclave to form a dissolved copper nitrate trihydrate; mixing trisodium citrate and ammonium fluoride into the dissolved copper nitrate trihydrate at a temperature less than 23° C. to form a solution; heating the solution in the PTFE lined autoclave at a temperature over 120° C. for more than 10 hours; centrifuging the heated solution and removing excess liquid from a CuO precipitate; washing the CuO precipitate with ethanol and water; drying the washed CuO precipitate at a temperature less than 150° C.; and calcining the dried CuO precipitate at a temperature greater than 300° C. to form the CuO.
 6. The method of claim 1, wherein the Cu—Ag₃PO₄ nanoparticles comprise copper in an amount of 2-7 wt.%; and have a mean surface area of 2.5-3.5 m²/g; a mean pore size of 20-30 nanometer (nm); and a mean pore volume of 100-200 cm³/g.
 7. The method of claim 1, wherein the Cu—Ag₃PO₄ nanoparticles comprise copper in an amount of 8-13 wt.%; and have a mean surface area of 3.8-4.8 m²/g; a mean pore size of 25-35 nm; and a mean pore volume of 100-200 cm³/g.
 8. The method of claim 1, wherein the Cu—Ag₃PO₄ nanoparticles comprise: copper in an amount of 14-18 wt.%; and have a mean surface area of 5.5-6.5 m²/g; a mean pore size of 15-25 nm; and a mean pore volume of 200-300 cm³/g.
 9. The method of claim 1, wherein the Cu—Ag₃PO₄ nanoparticles comprise: copper in an amount of 19-23 wt.%; and have a mean surface area of 6.5-7.5 m²/g; a mean pore size of 20-30 nm; and a mean pore volume of 250-350 cm³/g.
 10. The method of claim 1, wherein: the Cu—Ag₃PO₄ nanoparticles are substantially spherical; and the Cu—Ag₃PO₄ nanoparticles have a mean particle size of 100-1000 nm. 11-20. (canceled)
 21. The method of claim 1, further comprising: exposing the mixture to UV light.
 22. The method of claim 1, further comprising: exposing the mixture to UV light during the sonicating.
 23. The method of claim 22, wherein the mixture is exposed to UV light for no more than 10% of a total time of the sonicating.
 24. The method of claim 1, wherein the nanoparticles are aggregated to form clusters having an average size of 400 nm.
 25. The method of claim 1, wherein the Cu—Ag₃PO₄ nanoparticles comprise copper in an amount of 10 wt% and have a pore size of about 29 nm and a pore volume of about 0.014 cm³/g. 